New Sol-Gel Routes to Organic-Inorganic Hybrid Materials: Modification of Metal Alkoxide by Phosphonic or Phosphinic Acids

Hybrid materials were synthesized by modification of Ti(OⁱPr)₄ by diphenyl phosphinic (DPPA) or phenyl phosphonic acid (PPA). Different P/Ti and H₂O/Ti ratios have been investigated. The samples were characterized using FTIR and ³¹P MAS NMR spectroscopies, elemental analysis (EDX), and N₂ adsorption-desorption experiments. Both PPA and DPPA act as chemical modifiers. Depending on the H₂O/Ti and P/Ti ratios, and on the nature of the modifier (PPA or DPPA), molecular Ti oxo-alkoxo-phosphonates or phosphinates, stable sols, gels, or precipitates were obtained. In addition, the P/Ti ratio was retained during the hydrolysis whatever the H₂O/Ti ratio.